From bdced438acd83ad83a6c6fc7f50099b820245ddb Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 20 Oct 2015 23:13:52 +0800 Subject: [PATCH] block: setup bi_phys_segments after splitting The number of bio->bi_phys_segments is always obtained during bio splitting, so it is natural to setup it just after bio splitting, then we can avoid to compute nr_segment again during merge. Reviewed-by: Jeff Moyer Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-merge.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index c4e9c37f3e38..22293fdf6514 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -11,13 +11,16 @@ static struct bio *blk_bio_discard_split(struct request_queue *q, struct bio *bio, - struct bio_set *bs) + struct bio_set *bs, + unsigned *nsegs) { unsigned int max_discard_sectors, granularity; int alignment; sector_t tmp; unsigned split_sectors; + *nsegs = 1; + /* Zero-sector (unknown) and one-sector granularities are the same. */ granularity = max(q->limits.discard_granularity >> 9, 1U); @@ -51,8 +54,11 @@ static struct bio *blk_bio_discard_split(struct request_queue *q, static struct bio *blk_bio_write_same_split(struct request_queue *q, struct bio *bio, - struct bio_set *bs) + struct bio_set *bs, + unsigned *nsegs) { + *nsegs = 1; + if (!q->limits.max_write_same_sectors) return NULL; @@ -64,7 +70,8 @@ static struct bio *blk_bio_write_same_split(struct request_queue *q, static struct bio *blk_bio_segment_split(struct request_queue *q, struct bio *bio, - struct bio_set *bs) + struct bio_set *bs, + unsigned *segs) { struct bio_vec bv, bvprv, *bvprvp = NULL; struct bvec_iter iter; @@ -106,22 +113,30 @@ new_segment: sectors += bv.bv_len >> 9; } + *segs = nsegs; return NULL; split: + *segs = nsegs; return bio_split(bio, sectors, GFP_NOIO, bs); } void blk_queue_split(struct request_queue *q, struct bio **bio, struct bio_set *bs) { - struct bio *split; + struct bio *split, *res; + unsigned nsegs; if ((*bio)->bi_rw & REQ_DISCARD) - split = blk_bio_discard_split(q, *bio, bs); + split = blk_bio_discard_split(q, *bio, bs, &nsegs); else if ((*bio)->bi_rw & REQ_WRITE_SAME) - split = blk_bio_write_same_split(q, *bio, bs); + split = blk_bio_write_same_split(q, *bio, bs, &nsegs); else - split = blk_bio_segment_split(q, *bio, q->bio_split); + split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs); + + /* physical segments can be figured out during splitting */ + res = split ? split : *bio; + res->bi_phys_segments = nsegs; + bio_set_flag(res, BIO_SEG_VALID); if (split) { bio_chain(split, *bio); -- 2.39.5